


Better Your Ass Than Mine

by CaitieLewd



Category: Undertale (Video Game)
Genre: Anal, Anal Training, BDSM, Bondage, Consensual bondage, Dildos, Dom/sub, Electricity, Erotic Electrostimulation, Fellcest - Freeform, Fontcest, Fucking Machine, Gags, M/M, Masochism, Objectification, Orgasm Control, S&M, Sadism, Sex Machine, Toys, Underfell, Vibrators, Whipping
Language: English
Status: Completed
Published: 2017-10-11
Updated: 2017-10-11
Packaged: 2019-01-09 05:39:44
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,146
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/12270009
Author URL: https://archiveofourown.org/users/CaitieLewd/pseuds/CaitieLewd
Summary: Red wants to be pushed to his limits, and Edge is more than happy to whip him into shape.





	Better Your Ass Than Mine

**Author's Note:**

> And we're back! Welcome to day 11! Where we’ve got S&M, orgasm denial, and gags, OH MY~! Prepare to see a LOT of Fellcest this month, haha. I tried not to use them TOO much, but when it comes to doing kinky stuff consensually, they’re just the most natural pairing in my head. Them and Swapfell, of course.
> 
> Ravvi once again Beta'd this story, and on top of that she's been making drawings for each of these stories for kinktober, INCLUDING this one! Check out her amazing art at ravvi-k.tumblr.com!

“SO, BROTHER, YOU WISH TO BE PUSHED TO YOUR LIMITS? TO PROVE YOUR LOYALTY AND SUBSERVIENCE TO ME?” Edge spoke with uncharacteristic softness as he studied his wall of tools. Some appeared to be tools of torture, others tools of pleasure, but all were both, if used correctly.

He expected no answer—as he and his brother agreed upon before they began. Everything had been planned out, though some of the details he’d given his brother had been vague.

It was more fun that way.

Red was on his stomach, bent over a wooden, sawhorse-shaped bench with each hand and foot securely tied to the bench’s legs. Extra rope also secured his femurs and the base of his spine just before his sacram began,and the whole thing was bolted to the concrete floor of their basement,to ensure the small skeleton had not an inch of wiggle room. A bright red ball gag was wedged in his already-salivating mouth, and he was completely naked save for his ever-present collar. That was attached to a special clip right below his neck on the bench.

“HONESTLY...I THINK YOU’RE JUST A MASOCHIST AND A SLUT, BUT I SUPPOSE WE SHALL SEE WITH TIME.” At last Edge selected a tool and stepped in front of his brother, holding the object out of view behind his back.

“DO YOU REMEMBER THE SIGNAL, BROTHER?” Edge asked quietly.

Red nodded, snapping his fingers twice. Edge nodded back, and put on his mask of calm, yet stern, authority. He stepped behind Red, completely out of view, and the little skeleton’s SOUL began to thrum.

The whistle of a whip sounded, and Red braced himself, clenching his fists and biting down hard on the gag. But instead of the harsh sting of leather cords, Red felt the soft caress of a leather glove, stroking his sacram a few times before tracing its way down his down his ischium and straight to his pubic symphysis.

He moaned appreciatively, body relaxing as an ass and pussy coalesced almost instantly. Edge smirked. His brother was going to regret giving in so quickly.

The tall skeleton drew a finger down the dripping slit, and Red shuddered. “EAGER, ARE WE?” Edge chuckled. Red responded by clenching his pussy and buttocks, the only movement he could manage to increase the friction against the teasing finger.

Edge withdrew and stood.

**_THWACK_ **

The whip struck Red’s right ass cheek, raising a small welt and drawing out sharp cry. His head rose up, only to be snapped short by his secured collar.

A single corded bullwhip, Red realized, a shudder of true fear rattling through his bones. His brother had used it a handful of times—only during their most intense sessions. If he was _starting_ with that…

**_THWACK_ **

“mmmmhhhph!” Red screamed, twisting in his unyielding bonds, searching for a way to channel the hot sting of pain flaring through his left side. The sting had only just faded to a muted buzz when the whip whistled behind him again, and the small skeleton whimpered, then screeched as the whip rose another welt to match the first two.

Edge silently focused on his work, choosing the location of his next strike carefully. After so many years of this sort of play, he was intimately familiar with his brother’s limits, and how and where he could inflict pain without actually inflicting any damage. There were a few thresholds they still had not crossed, however, and Edge planned on doing everything in his power to push his brother across one today.

But first, the small skeleton had to be prepared.

The whip caught Red on the upswing this time, striking the underside of his buttocks and frighteningly near his sensitive pussy. “mmmmmm-hn-hn-hnnn!” he groaned, tears already pricking at his eye sockets. Just as he began to recover, he was struck on the side of his hip, then the right ass cheek again, then the underside of the other cheek. Again and again and again, a deliberate series of strikes without being repetitive enough for him to anticipate the location of the next blow.

When the whip came down squarely on the border where his flesh connected to the bare bone above his sacram, Red let out a particularly agonized howl, and his brother actually paused for a moment. They couldn’t have been at it more than a few minutes, but Red was already a sweaty, shaking mess. His breathing was ragged, pushing his spine up and down against the surface of the sawhorse as tears painted shining trails down his cheeks.

Red hadn’t realized how much he relied upon giving feedback to cope with the pain of their sessions. Counting, thanking his boss for each strike, even begging and bargaining. Speaking—or even attempting to speak around a gag—gave him an outlet and a way to track their progress in the session. Illogically, it gave him some semblance of control over the situation. But remaining silent beyond his cries of pain was a new level of agony. Robbed of even the illusion of control, he was a helpless object, a whipping post to be punished again and again until his boss saw fit to stop.

“BROTHER, THE SIGNAL?”

There was a concerningly long pause before Red snapped twice. The torture began again. The room’s walls echoed with only the whistle and fleshy slap of the whip, and the sound of Red’s stifled suffering.

He had to find another outlet for this pain. Somehow, some way…

Red closed his eyes and focused on the buzzing feeling that came after the initial sting. In a way, it felt like his skin was warm and vibrating. Almost like a massage...with a whip. He knew that was the moment his body was releasing endorphins to dull the pain.

He made those moments between the blows his entire world. His body hummed with energy, his feeble healing magic crackling to the surface to inspect and fix any damage it found. There was none, but that didn’t stop his body from checking. Red stopped trying to anticipate the strikes and only endured, living for the buzz and heat which was slowly penetrating all of his bones.

With more time, Red’s yelps and cries became steady hums and moans. Not necessarily of pleasure, but his shrieks no longer surged each time the whip struck flesh or bone.

Edge watched him carefully, aware the moment his brother began to adapt to the whip. Good. That meant it was time for a change.

Edge stepped back over to his tool wall and hung up the whip, then selected two new instruments. A massaging wand, and an entirely different wand which was long, cone shaped, and had a blunt, rounded end. He took the massage wand and pressed it against Red’s folds, nestling it snugly against his labia and clitoris.

The small skeleton stirred and mumbled something into the gag, apparently having been lulled into a trusting, trancelike state by the sustained whipping. Well, that could be fixed. With a small grin, Edge switched on the massage wand.

A loud buzzing filled the room and Red jolted, his eye lights flashing bright as the chain around his neck tugged him short with an abrupt jerk. “hhhhgh?!” he squeaked, just before a wave of bliss went crashing through his cunt and drained all the fight from his body, his bones practically melting into the sawhorse. The feeling of true pleasure after so much pain was magnificent. He temporarily forgot about his vow of silence and tried to thank his brother, but the words lost coherence and dissolved into moans, a new stream of drool trailing down his chin.

“IS THAT FEELING BETTER? GOOD,” Edge purred. He was giving him the entire head of the wand, holding the tip securely against his pussy with a slow, rocking motion to keep the vibrations from numbing the area.

Red was far too gone to be suspicious of his brother’s sudden generosity, which made, the spark of electricity that crackled in the air and through his sensitive, abused ass a harsh shock.

**_ZZK!_ **

“ghk?!” he choked, his whole body jolting. An electric wand, too?! His SOUL filled with dread once again. It was blurred out as, moments later, the vibrating wand took his attention again. But his brother showed no mercy. In rapid succession Red received a zap on his other buttock, his hip, his femur, then dangerously close to his anus.

He shrieked in pain and frustration, balling his fists and trying to shake his collared neck side to side. The shocks were _so_ much worse than the whip. His bones were already hot and sensitive, and the electricity hurt but didn’t have the soothing afterglow the strikes had. The only reprieve was the massage wand still working at his pussy, which he could feel again during the few seconds of reprieve between shocks.

The tip of the electric wand touched his ass again and Red flinched. But nothing came. Edge chuckled sinisterly, then dragged the tip gently across Red’s hot, inflamed skin, tracing intricate patterns that had smaller skeleton squirming under his touch. Just as Red’s bones began to relax again, Edge pressed the button.

**_ZZK!_ **

“hhhgh!” Red cried, pulling tight in his bonds. The next several minutes became a game of Edge giving him a shock in a random location near his posterior each time he let his guard down. Which was pretty frequent. Red had just become accustomed to relaxing during the flogging but his boss was forcing him to change gears again, making him focus on his torture and find a way to cope with the pain...which was likely supposed to be the massaging wand…

Red knew he wasn’t supposed to come this soon, and that made giving in to the vibrations a dangerous choice. But it was the only one he had left to him. Using what little wiggle room he had, the small skeleton pressed his pussy harder against the wand, moaning softly as the deep vibrations sunk in like a soothing balm. That was apparently the right choice, as Edge tilted the wand up in response, giving his clitoris an even better angle.

Once again Red found himself in a timeless hell, endlessly running the gamut between torment and bliss. He refused to count or even acknowledge the shocks, only focused on the glorious rhythm of the powerful vibrations directly up against his cunt. Though that was easier said than done—his brother was making the shocks hard to ignore, some even lingering a second or two before letting off.

Red bit down hard on the gag, grinding it between his teeth. It was so much stimulation, so much _pain._ Should he...should he call it? He wasn’t sure how much longer he could keep going on this way...

He jolted when the massage wand pulled away for a second, giving just enough room for the electric wand to shock his outer folds. _Ooooh_ that was...he wasn’t sure what, but he knew he loved this. Totally helpless, completely in the dark of what this was all leading up to, and the object of absolute focus for his brother. His brother—his Boss—whom he loved and cared for the most in this hellhole of existence. The very thought of Papyrus’ sharp, focused intent being bent on achieving the perfect balance of pleasure and pain sent a bolt of need through Red’s cunt. He moaned long and loud, feeling the head of the massager slip feely across his dripping cunt.

Yes, he could do this. There was nothing his brother would push him toward that Red couldn’t do. He would see this through to the end, whatever Boss had planned.

Edge found himself glad his brother was tied so that he couldn’t see him, he wasn’t sure he wanted Red to see the look of pride he knew was spread across his face. Red was doing _so_ well, coping with everything he threw at him like a champ, bringing himself to levels of pain, pleasure, and trust they’d never approached before. The small skeleton was almost ready for the main event, and while it was tempting to go ahead and reward him for getting this far, he knew that would only ruin everything.

Red’s moans of bliss began to peak. “OH NO YOU DON’T,” Edge tutted, then removed the massager from Red’s cunt and stepped away.

“nnnnnnngh!” Red cried out, almost as loud as he’d cried out from the first electric shocks. _no, please Boss, please let me come!_ he wanted to scream. He vented his frustration by flailing his bonds and grinding his teeth against the gag, letting out a pathetically miserable howl.

The small skeleton’s pitching and moaning masked the sound of the next tool Edge moved into position. It took a couple of minutes to get into place and align. Just as Red recovered from his fit long enough to wonder what was happening, a mechanical whirr sounded and a large, soft, silicone shaft plunged deep into his pussy and stopped.

“mmmph?!” His struggles ceased. The member had filled him up instantly, sliding in with no resistance and lodging deep inside his cunt.

“THAT STOPPED YOUR CATERWAULING, DIDN’T IT?” Edge said with a smirk. Red breathed shallowly, desperately pushing as fard back against the ropes as he could, trying to move against the shaft to no avail. The member pulled out a few tantalizing inches, then pushed back in to bottom out once more.

Red panted and arched his back, the ropes around his spine creaking. Just a few more, please Boss, so close, so close, so _close…_

The shaft pulled all the way out with a wet pop, and Red whined petulantly.

“NYEH HEH HEH HEH!” Edge cackled. “DID YOU THINK THAT WAS FOR YOUR _PUSSY?_ OH, NO…” He made an adjustment to the machine with a cold ratcheting noise. “THAT WAS JUST FOR LUBRICATION…”

Red didn’t have time to react before the machine whirred again, and the member made firm contact with his clenched anus.“mmmmmgk?!” Red squawked. He went absolutely still as the shaft pushed its way in, slowly but surely. He fought instinct to squirm, but he couldn’t bring himself to relax and ease its entrance. When the head cleared his sphincter a small part of Red accepted his fate, and his muscles unclenched just slightly, allowing it to carve a path through his passage. When the shaft had fully penetrated him it stopped, making Red feel much more stretched and full than he’d felt when it had been in his pussy.

“THIS IS WHAT WE HAVE BEEN WORKING TO,” Edge announced, moving to the front of the sawhorse, one hand hidden behind his back and the other holding a remote in one hand. He tilted Red’s face up with a clawed finger, meeting his weary and fearful eyes directly. “TODAY, YOU ARE GOING TO COME FOR ME, USING ONLY THIS.” He pressed a button on the remote and the shaft pulled nearly all the way out, then slowly pumped back in, repeating the motion with a tireless, lazy pace.

Red groaned, staring at his brother with shocked, pleading eyes. They had done anal play many times before, mostly with plugs, beads, and hooks, and this wasn’t the first dildo he had taken, either. The only downside was that Red had never been able to come from anal stimulation before. Not alone, anyway. He liked it, and it definitely enhanced their sessions, but he always needed something else along with it to send him over the edge.

“THIS WILL NOT STOP UNTIL YOU COME, SO YOU’D BEST HOP TO IT.”

**_ZZK!_ **

“hhhgh!” The electric wand shocked Red’s shoulder and he lurched. Apparently Edge hadn’t put took away, either. Great.

There were no more shocks after that, however. No whips either, not even an affectionate slap or stroke. There was only Red, and the huge silicone dildo relentlessly fucking his ass.

At first, he could only feel the stinging betrayal, as he knew this was an impossible task. He struggled futilely in his bonds, fighting them and the member with petulant defiance. But he was wearing out, the exhaustion of his previous struggles weighing down his bones and making him crave _any_ kind of positive stimulation.

Yes, he had to stop fighting, Red thought. His brother wouldn’t do this to him without believing he could. He had to try, he had to at least _try_ to be worthy of his Boss’ belief in him. At last he gave in, relaxing his muscles and letting the member take him willingly.

The machine continued at the same slow pace, but Red’s harsh yelps gradually gave way to long, moans and hums that escaped him like chants, or prayers. The small skeleton became intimately familiar with the shaft, painfully aware of its bulbous head, the thick, rough veins carved down its length, and the slight curve up in the middle which gave it even more resistance as it pillaged him. The stimulation felt divine and Red’s cunt pulsed urgently, but it just wasn’t enough—!

.

There was a very specific type of satisfaction Edge always felt when his brother was fucked in the ass, whether by him or by one of his toys. The sounds the small skeleton made were unique and exquisite—moans that ended in abrupt grunts, as though he were being punched repeatedly from the inside. His eyes closed, his fists clenched, his toes curled. Adorably, his knees tilted inward, and his ass stuck up every so slightly in the air—as much as it could under the circumstances. He looked like a battered, helpless doll being drilled from behind.

But Edge could see the strain was from determination, not resignation. Sweat poured off of Red in streams, running down his vertebrae and ribs in spirals and soaking into the wood of the sawhorse. His face was pinched in concentration, searching for that sweet spot which would allow him to climax.

The taller skeleton hovered over his brother, hands patiently clasped behind his back as he ratcheted the speed of the shaft up a notch. He hoped Sans found satisfaction soon...but not _too_ soon. He wanted to carve this image of his fragile, resolute brother onto the inside of his skull forever, so that if ever he doubted himself, he could think back and remember how bravely his brother had faced this impossible task.

.

Five minutes passed. Edge continued to slowly increase the speed, and adjusted the thrusts to go a little shallower.

Ten minutes passed. The shaft was moving at a respectable clip, but still Red was nowhere near a climax. His labia were blooming and engorged, trickling fluids steadily onto the floor, but his SOUL never sparked. His breath came in deep, rhythmic pants that matched the pace of the machine.

Edge hummed thoughtfully. He lowered the speed and made the thrusts deeper again, trying to work him up slower. Again he dialed up the intensity, even supplementing more lubrication at 15 minutes.

At 20 minutes, Edge seriously considered calling it off. Red appeared to be in no immediate danger, but he was showing signs of physical and magical and exhaustion. He decided to give him five more minutes.

Perhaps Red also realized his time was short, as his attempts to come had become downright desperate. He forced a moan from his sore throat, he twisted his stiff hip joints and did what he could to meet the untiring shaft. Edge took note of this final attempt, and brought the machine to its maximum setting.

“mmmmm, hnnnnnn, hfff!” Red panted, tears of frustration rolling down his face. He’d been on the edge for so long, he swore he would dust if he didn’t get his release soon. The member was pounding him now, annihilating his ass, pushing his entire body forward against the sawhorse with each blow. His pussy throbbed hard and he screamed, focusing on growing that tiny point of pleasure deep inside him. If the shaft had been pummeling his pussy, he would have come a dozen times over by now, so why—couldn’t—he—come—!

The five minutes passed, and at last Edge had an epiphany. Smirking, he brandished the electric wand once more, and brought it within a hair’s breadth of Red’s throbbing, exposed clitoris. He pressed the button.

**_ZZK!_ **

_“HHHHGAAAAAAAAAAAH!!!”_

Red came so violently that Edge instantly checked his HP. His eye lights went out and every rope holding him down pulled taut. Juices squirted and gushed from his cunt, splattering Edge’s pants and boots. And his SOUL—his glittering, wondrous SOUL—exploded with pure light that danced all around the room.

The small skeleton remained in rapture for nearly a full minute. It didn’t help that the shaft was still pounding away, drawing out the climax for an impossibly long time. Edge’s finger hovered over the remote’s emergency stop button, watching his brother’s ecstasy carefully. He had never seen anything like this before. The parts of him that weren’t concerned for his brother’s well-being were utterly fascinated, and getting very aroused.

At last Red collapsed against the sawhorse, gasping for air, fairly certain he had lost some time, there. But the afterglow which still pulsed through his cunt, ass, and SOUL was impossibly divine. Was this really him? Had his body just done all this, made him feel _this_ good? Had he really come so hard he _passed out?_ Whoa. He was going to have to thank his brother big time.

“WELL DONE, BROTHER,” Edge praised, nudging the straw of a water bottle toward Red’s teeth. When had he moved in front of him again? And when had he gotten water?

The gag was out of his mouth, and Red’s tongue pulled in the straw instinctively. Edge spoke softly and tenderly. “THAT’S RIGHT, BROTHER. SLOW, YOU DON’T WANT TO MAKE YOURSELF SICK.” He held the water bottle steady and unclipped the collar with the other. Red drank as instructed, content to slowly wet his mouth and enjoy the simple sensation of cool water running down his throat. His head felt fluffy and light, even the smallest sensations felt tingly and delightful.

The machine had exited Red and was completely powered off, the room was quiet except for the sound of Red’s slurping and Edge’s gentle praises. When Red had drank his fill, he looked up at his brother.

“so what now, bro? should we do you next? that was great, but…” He glanced away for a second, a slight flush spreading over his cheekbones as his gaze settled to his brother’s tented leather trousers. “don’t you...i...i mean...i can still…”

Edge cocked an eye ridge. “YOU WANT ME TO FUCK YOU, IS THAT IT?” he asked flatly.

Red’s gold tooth sparkled in the basement light as he chuckled. “heh heh heh...well, i want you to feel good too, boss.”

It was Edge’s turn to blush. Abruptly he cleared his throat. “AHEHEM. WELL, RUNT, IF YOU REALLY THINK YOU’VE GOT IT IN YOU FOR A SECOND ROUND, PERHAPS WE CAN FINISH YOUR TRAINING, FIRST.”

A button on the remote clicked, and the fucking machine pumped forward just enough for the head of the shaft to press insistently at Sans’ now loosened and tender passage.

“WHAT DO YOU SAY?” Edge dangled a fresh gag in his hand. This one was similar to the ball gag, except instead of a single ball, there was a line of three round balls which became successively smaller. “THINK YOU CAN DO THAT TWO MORE TIMES FOR ME? I PROMISE I’LL MAKE IT WORTH YOUR WHILE…”

Red swallowed hard, eyeing the gag with no small amount of trepidation. If he was honest with himself, he felt like he’d been fisted by a ficus, and the rest of his body was still sore and glowing a brilliant red from the prior beatings.

But he also couldn’t deny that orgasm had made him feel like a whole new monster, and the only thing he wanted now was to make his brother happy.

“yeah, boss. bring it on. fuckin’ destroy my ass if you gotta.” Red opened his salivating mouth wide and stuck his tongue out, ready to accept the gag.

“BE CAREFUL WHAT YOU WISH FOR, BROTHER,” Edge warned lightly. He clipped his brother’s collar back in place and inserted the large, beaded gag, pausing to listen with tremendous satisfaction to the obscene sounds Red made as he shifted the extra silicone balls around in his mouth. He wasn’t sure if he was going to offer his brother help this time, the whole point of the anal training was to get him to come without any vaginal stimulation. But if it kept him making sounds like _that_ , he may have to spoil himself and do something to “feel good, too.”

**Author's Note:**

> WHEW OKAY. Yet another one that got away from me in terms of length. I JUST REALLY LOVE THESE KINKS OKAY.
> 
> So yeah, basically Edge put him through all that whipping and shocking to get Red into the mindset of redirecting feelings, such as pain and pleasure. That way he could hopefully redirect the anal stimulation to get him to come. And it worked...more or less. It wasn’t a GOOD feeling Edge gave him to send him over the edge, lol. Poor guy’s gonna be sore for months. And he’ll go into heat every time a door knob shocks him.
> 
> I’m posting this as a stand-alone, but there is another Fellcest story I have planned later this month that has to do with anal. It’s non-con, and while technically it could be in the same timeline, it won’t directly reference this one and I don’t consider them part of the same story. But y’all feel how you feel about them, I won’t stop you lol.
> 
> This may be way TMI, but I based Red’s reaction to his orgasm on how I feel after a great sexual experience, haha. Sometimes after a particularly crazy orgasm I’m just like “Holy shit my body DID THAT?!?!” And I just lose my shit for a while. And when it’s my bf who made it happen, I want to make him feel good in return, even if he started out totally cool letting me receive.
> 
> Tomorrow we return to the Gaster/Human story from day 7! The kink is medical play, and it is in no way, shape, or form consensual.


End file.
